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"I would say that 99 of us believe the Russians did this," Graham said

Graham and McCain were frequent critics of Trump during the campaign

(CNN)Two of the Senate's most prominent hardliners on Russia are framing the Washington consensus of Russian aggression as free from any disagreement whatsoever -- except from President-elect Donald Trump.

Republicans Lindsey Graham and John McCain, on a trip to Estonia, a Baltic nation threatened by a belligerent Russia, told CNN's Jim Sciutto in an exclusive interview that the matter was settled and that Trump was simply wrong to question the bipartisan agreement.

"There are 100 United States senators. Amy Klobuchar is on this trip with us. She's a Democrat from Minnesota. I would say that 99 of us believe the Russians did this and we're going to do something about it," said Graham, who is planning a hearing with McCain on Russia's interference with US elections. "We're going to put sanctions together that hit Putin as an individual and his inner circle for interfering in our election, and they're doing it all over the world -- not just in the United States."

McCain, Graham and Klobuchar are also headed to Latvia, Lithuania, Ukraine, Georgia and Montenegro to meet with officials about the Russian threat. The intelligence community has formally blamed the Kremlin for interfering in the most recent presidential election, using sophisticated hacking schemes and cyber intrusions to expose the emails of Democratic Party officials.

Graham and McCain were frequent critics of Trump during the campaign, and raised alarms about Trump's relationship with Vladimir Putin, who Trump has praised as a "strong leader."

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McCain also reiterated his worries about Rex Tillerson, the retiring ExxonMobil CEO whom Trump has chosen to lead the State Department. McCain declined to say whether there would be a confirmation showdown next month in the Senate, noting that presidents tend to have the right to pick their own advisers. But McCain said he had "concerns" about Tillerson's favorable posture toward Putin and Russia.

McCain expressed confidence, however, that Trump would "change his view" toward Russia -- and specifically their role in the cyberattacks -- once he becomes commander in chief and is "presented with the overwhelming evidence."

Some Trump positions, such as those against Iran and China, have endeared him to his party's hawks. Graham saluted those views but said that if Democrats and Republicans alike did not smack back at Putin, it would embolden the nations that Trump believes are geopolitical threats.

"If we don't push back against Putin, Iran and China -- they could hack in to our systems," Graham said. "Today it's Democrats, tomorrow it could be Republicans with the Iranians and the Chinese."